Mastitis continues to be a major cause of economic loss in the dairy industry even though there are methods of treating this disease. Currently, the primary method of treating mastitis in cows (inflammation of the udder) as well as treating metritis (inflamation of the uterus) is antibiotic therapy. However, antibiotics thus used tend to leave residues in the milk so that milk from cows treated with antibiotics must be kept from human consumption.
This discarding of the milk from the cows under treatment is one of the more expensive aspects of mastitis. Yet, there are several reasons that milk contaminated with antibiotics should not be sold. Some people are allergic to antibiotics, especially penicillins, and fatalities have occurred relating to allergic reactions. If milk gains a public reputation for containing antibiotics, then sales of liquid milk might decline rapidly. Antibiotics consumed by humans at low dilute levels will allow various pathogenic bacteria that are currently sensitive to these antibiotics to become resistant.
Further, antibiotics can destroy the bacterial cultures used in yogurt and cheese manufacture. Finally, present regulations require milk from treated cows to be kept from the human food chain for three days. New regulations of longer holding times that are envisioned can deal the dairy industry a devasting impact.